Method of producing a combined line and half-tone printing plate.



PATENTED JAN. 29, 1907. G. BRADT.

0. A. BON PILS & H METHOD DP PRODUCING 1. COMBINED LINE AND HALF TONEPRINTING PLATE.

APPLICATION. FILED NOV. 28, 1906.

2 SHEETS-SHEET 1.

T 11v VEN TORJ C, A Eon-( H5 mmIlll BYv - 'PATENTED JAN. 29, 1907. G. A.BONFILS & H. G. BRADT. METHOD OF PRODUCING A COMBINED LINE AND HALF TONEPRINTING PLATE.

APPLICATION FILED NOV. 28, 1906.

2 SHEETS-SHEET" 2.

I 1 UNITED STATES CHARLES ALDEN BONFILs A-ND HORACE e. .BRADT,QF'DENV-ER, .ooLoRADo.

PATENT OFFICE.

METHOD'OF Pnonucme A cemamzn um: Am) IHALETONE PRINTING PLATE; 1

tion. v

The invention relates to an improved process of producing combined lineand half-tone printing plates, and has for its object t'o'obviate by theuse of a simple mechanical process the laborious and skill-requiringmethod of lifting, cutting, and replacing the films on the negatives'nowcommonly employed to obtain the desired effect.

2 tone The various stepsemployed in practicing our method areillustrated in the accompanying drawings, in the various views of whichlike arts are similarly designated, and in which- Figure 1 representsthe photograph or wash-drawingto be re roduced by the half:

process; Fig. 2, t e line-drawing to be repro need in combination withthe photo graph or tint-drawing shown in Fig. 1 Fig. 3,

the two representations in combination ready uction Fig. 4, a negativephoto- Fig. 3, t e linework being ainted out Fig. 5, a negativephotographic plate of the line-drawing; Fig. 6, a reproduction of thelatter upon the metal printing-plate; Fig. 7,

' the completed printing-plate, and Fig. 8 an impression takentherefrom. I

Referring to the drawings, 5 des'i ates a icture, such as a photographor was drawmg, adapted to be re roduced by the halftone process, and 6 aine-drawing executed for the purpose of zincographic reproduction andprovided with diagonally-disposed registering marks 7. a

' The first step in our process consists in cutting-out those portionsof the drawing 6 where on the finished'plate the half-tone work is toapear, after which the skeleton mask thus 0 tained is placed in thedesired position over the picture shown in Fig. 1, as illustratedinFig.3. The combinedrepresentations are now reversedly reproduced upon aphotographic plate by'means of a camera equipped with a prismatic lens.The

negative thus obtained isby interposition between the original and thelens of a screen,

Specification of Letters ratent. I Application filed November 28, 1906.Serial No. 345.621.

Patented Jan. 29, 1907.

adapted for photo-engraving, or, with other words, the solid tints ofthe original are represented on the plate b a multitude of juxtaposeddots or lines. Iii part of our invention it should be observed that inlieu of using a rismatic camera the negative may be made b means of anordinary lens and the film su sequently lifted off such as commonly inhalf-tone work,

connection withthis and reversedly replaced upon the glass. plate.

The next step of our rocess consists in paintlng out the repro uction'of the linedrawing on the negative byfcoveringthe extent of the skeletonmask (with the exception of the registering marks) with indi'a-ink orother suitable opaque substance, as illustrated in Fig. 4. A secondnegative isnow made of the line-drawing to a scale identicalwiththat'ofthe image on the first plate by .method 0- removing t escreen from the frame in which the two representations are .photograplhin the skeletonmask" placed upon a w :te ckg'round to obtain theeffect o the ori inal drawin' or' by the simpler held and interposing asheet of white paper As. the last named op.-

the' camera, it is obviously preferable to the. first-named method. Theimage on the lastmade. negative, which like the one on the I I firstplate is reversedly produced thereon, is

now reproduced upon a zinc or copper plate previously coatedwithbichromate of ammonia or other sensitive substance by the ordinarymethod of placing the one upon the. other in a printing-frame andexposing the latter to the action of light. The sensitized surfaceof'the metal" plate (illustrated in Fig;

6) is now developed in the usual manner and preferably coatedwithphoto-engravers ink to render the impression, and more especiallythe re 'stering marks, discernible, after which t e plate isresensitized and replaced in the printingframe beneath the painted outnegative, (shown in Fig. 4,) care being taken that the marks 7 on thenegative and half-tone work, are reproduced upon the i I plate,with theresult that when after exposure the plate is developed it contains, asillustrated in Fig. 7 the combined impressions of the photographillustrated in Fig. 1- and the frame.

To thoseskilled in the art to which our invention pertains. its manyadvantages will be apparentas the method of coating the negative'withrubber and colodion and removing, cutting,-and replacin its film asheretofore employed has at al times been associated with suchdifficulties as shrinking, shriveling, turning under, and lapping of thefilms, the forming of air-bubbles between the film and the glass, &c.,and can only be prac ticed by highly-skilled persons.

It will be understood fromthe foregoing that our process is adapted forthe production of printing plates having either'an enamel or an albumensurface. g

Havingthus described our invention, what we claim is 1. The method ofroducing combined line and half-tone printing plates, consisting inmakin a negative bearing the reversed image of a photograph ortint-drawin and the reversed ontline reproduction of a inc-drawingcovering the image of the line-drawing on the\ said negative with anopaque substance, producmg a second. negatlve bearing a reversed imageofthe line-drawing, successively pro ducing prints of the two negativesupon a sensitized metal late, and etching the latter. g 2. The met 0d ofproducing combined line and half-tone printing plates consisting inskeletomzmg a line-drawing, making a re-, versed negative of the latterand the original photograph or tint-drawing, covering the image of thesaid skeleton upon the negative with opaque substance, producing asecond, reversed negative of the line-drawing, sucoessively producingprintsof the two negatives upon the sensitizedsurface of a metal plate,and etching the latter.

3. The method of producing combined line and half-tone printing platesconsisting in skeletonizing a line-drawing, making a reversed negativeof the latter and the original photograph or tint-drawing, covering theimage of the said skeleton upon the negative with opaque substance,producing a second, reversed negative of the-line drawmg, producing aprint of the last-named negative upon the sensitized surface of a metalplate, developing and resensitizing the latter, producing a printthereon from the first negative, and etching the plate.

In testimony whereof we have affixed our signatures in presence of twowitnesses.

CHARLES ALDEN BoNFILs'. HORACE G. BRADT.

Witnesses:

' WM. H. EADER.

FRANK M. STORES.

